Everything below concerns Reversed-phase HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-05-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
The most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
Regulatory status varies by country and is not harmonized. Epitalon is not an approved drug in major Western jurisdictions. In some countries it is sold as a research chemical, and in others it has appeared in products marketed for other categories. This inconsistent status means that purity, labeling accuracy, and documentation differ widely between suppliers, and verification of identity and purity through independent analysis is the usual way buyers assess a given lot.
On the other side, courts and tribunals are theoretically under a duty to refer questions. In the UK, for example, Lord Denning MR considered it appropriate to refer if the outcome of a case depended on a correct answer, and the Civil Procedure Rules entitled the High Court to refer at any stage of proceedings. The view of the Court of Justice in the leading case, CILFIT v Ministry of Health is that a national court has no duty to refer if the law is an acte clair (a clear rule), or "so obvious as to leave no scope for any reasonable doubt as to the manner in which the question raised is to be resolved". In Kenny Roland Lyckeskog the Court of Justice held that the duty to refer existed for the Swedish Court of Appeal, the hovrätt, since Sweden's Supreme Court (Högsta domstol) had to give permission for appeals to continue. The practical difficulty is that judges differ on their views of whether or not the law is clear. In a significant case, Three Rivers DC v Governor of the Bank of England the UK House of Lords felt confident that it was clear under the First Banking Directive that depositors did not have direct rights to sue the Bank of England for alleged failure to carry out adequate prudential regulation. Their Lordships highlighted that while some uncertainty might exist, the costs of delay in making a reference outweighed the benefits from total certainty.
Fillod was interviewed by Stephanie Theobald, whose article in The Guardian stated that the 3D model would be used for sex education in French schools, from primary to secondary level, from September 2016 onwards; this was not the case, but the story went viral across the world. A questionnaire in a 2019 study was administered to a sample of educational sciences postgraduate students to trace the level of their knowledge concerning the organs of the female and male reproductive system. The authors reported that about two-thirds of the students failed to name parts of the vulva, such as the clitoris and labia, even after detailed pictures were provided to them. An analysis in 2022 reported that the clitoris is mentioned in only one out of 113 Greek secondary education textbooks used in biology classes from the 1870s to present. An editorial of the Journal of Biological Education in 2026 calls for a shift in the way reproduction is taught in biology classrooms, i.e. the current strong emphasis on procreation be complemented by a greater focus on sexual pleasure. It is then suggested that this could be achieved by increasing attention within biology education to the external female reproductive organs, especially the clitoris, by accurately illustrating its detailed anatomy and clearly explaining its function.
=== Oligosaccharides === Oligosaccharides may be sequenced using tandem mass spectrometry in a similar manner to peptide sequencing. Fragmentation generally occurs on either side of the glycosidic bond (b, c, y and z ions) but also under more energetic conditions through the sugar ring structure in a cross-ring cleavage (x ions). Again trailing subscripts are used to indicate position of the cleavage along the chain. For cross ring cleavage ions the nature of the cross ring cleavage is indicated by preceding superscripts.
== Pharmacology == The drug phencyclidine (more commonly known as PCP or 'Angel Dust') antagonizes glutamic acid non-competitively at the NMDA receptor. For the same reasons, dextromethorphan and ketamine also have strong dissociative and hallucinogenic effects. Acute infusion of the drug eglumetad (also known as eglumegad or LY354740), an agonist of the metabotropic glutamate receptors 2 and 3) resulted in a marked diminution of yohimbine-induced stress response in bonnet macaques (Macaca radiata); chronic oral administration of eglumetad in those animals led to markedly reduced baseline cortisol levels (approximately 50 percent) in comparison to untreated control subjects. Eglumetad has also been demonstrated to act on the metabotropic glutamate receptor 3 (GRM3) of human adrenocortical cells, downregulating aldosterone synthase, CYP11B1, and the production of adrenal steroids (i.e. aldosterone and cortisol). Glutamate does not easily pass the blood–brain barrier, but, instead, is transported by a high-affinity transport system. It can also be converted into glutamine. Glutamate toxicity can be reduced by antioxidants, and the psychoactive principle of cannabis, tetrahydrocannabinol (THC), and the non-psychoactive principle cannabidiol (CBD), and other cannabinoids, is found to block glutamate neurotoxicity with a similar potency, and thereby potent antioxidants.
is the differential that defines the integral over the whole volume of the system. The continuity equation for the mass is part of the Euler equations of fluid dynamics. Many other convection–diffusion equations describe the conservation and flow of mass and matter in a given system. In chemistry, the calculation of the amount of reactant and products in a chemical reaction, or stoichiometry, is founded on the principle of conservation of mass. The principle implies that during a chemical reaction the total mass of the reactants is equal to the total mass of the products. For example, in the following reaction
Sources: en.wikipedia.org
It is believed that the first documented European to explore the east coast of Canada was Norse explorer Leif Erikson. In approximately 1000 AD, the Norse built a small short-lived encampment that was occupied sporadically for perhaps 20 years at L'Anse aux Meadows on the northern tip of Newfoundland. No further European exploration occurred until 1497, when seafarer John Cabot explored and claimed Canada's Atlantic coast in the name of Henry VII of England. In 1534, French explorer Jacques Cartier explored the Gulf of Saint Lawrence where, on July 24, he planted a 10-metre (33 ft) cross bearing the words, "long live the King of France", and took possession of the territory New France in the name of King Francis I. The early 16th century saw European mariners with navigational techniques pioneered by the Basque and Portuguese establish seasonal whaling and fishing outposts along the Atlantic coast. In general, early settlements appear to have been short-lived due to a combination of the harsh climate, problems with navigating trade routes and competing outputs in Scandinavia. In 1583, Sir Humphrey Gilbert, by the royal prerogative of Queen Elizabeth I, founded St John's, Newfoundland, as the first North American English seasonal camp. In 1600, the French established their first seasonal trading post at Tadoussac along the Saint Lawrence. French explorer Samuel de Champlain arrived in 1603 and established the first permanent year-round European settlements at Port Royal (in 1605) and Quebec City (in 1608).
Initially, there may be a small ulcer in the mouth which progresses into necrotizing gingivitis – painful bleeding of the gums and inter-dental papillae. This is followed by a rapid spread of the infection resulting in more general inflammation of the mouth and lips, facial edema, and foul breath. If untreated, within a few days the necrotizing infection progresses into the facial muscles, the skin, and the upper and lower jaw resulting in tissue destruction and sloughing. Many patients die due to sepsis; survivors are left with permanent scarring and disfigurement. Noma neonatorum is a severe infection affecting very young or newborn children in impoverished environments. A gangrenous infection spreads across the oral, nasal, and/or anal areas, and is frequently fatal. The pattern of lesions is similar to those found in noma. The World Health Organization divides noma into five stages: Acute necrotizing gingivitis, edema, gangrenous, scarring, and sequelae.
=== Time and temperature indicators === Temperature indicators show that a specified temperature has been reached or exceeded. Time–temperature indicators respond to cumulative exposure over time and can provide an indication of the thermal history of a product. Indicators may use chemical, enzymatic, microbial, mechanical, electronic, or colour-changing mechanisms. They are used with foods, vaccines, pharmaceuticals, biological materials, and other temperature-sensitive goods. Electronic temperature data loggers can record the time, duration, and extent of temperature deviations. Thermochromic inks provide reversible or irreversible colour changes when particular temperatures are reached.
== Excitonic properties == First-principle calculations incorporating quasiparticle corrections and many-body effects have been employed to study the electronic and optical properties of graphene-based materials. The approach was described as three stages. With GW calculation, the properties of graphene-based materials were accurately investigated, including bulk graphene, nanoribbons, edge and surface functionalized armchair ribbons, hydrogen saturated armchair ribbons, Josephson effect in graphene SNS junctions with single localized defect and armchair ribbon scaling properties.
Sources: en.wikipedia.org
A common way to get more quantitative information out of a mass spectrum is to create a standard curve to compare the sample to. This requires knowing what is to be quantitated ahead of time, having a standard available and designing the experiment specifically for this purpose. A more advanced variation on this is the use of an internal standard which behaves very similarly to the analyte. This is often an isotopically labeled version of the analyte. There are forms of mass spectrometry, such as accelerator mass spectrometry that are designed from the bottom up to be quantitative.
== Competition == Two additional refrigerated train services were announced in 2013, the Green Express, from Tampa, Florida to Kingsbury, Indiana, operated by CSX and the Tampa Port Authority, and the TransCold Express operated by McKay Transcold and BNSF, connecting the California Central Valley with the midwest.
=== Prescription drug monitoring === In 2016, the CDC published its "Guideline for Prescribing Opioids for Chronic Pain", recommending opioids only be used when benefits for pain and function are expected to outweigh risks, and then used at the lowest effective dosage, with avoidance of concurrent opioid and benzodiazepine use whenever possible. Silvia Martins, an epidemiologist at Columbia University, has suggested getting out more information about the risks:The greater "social acceptance" for using these medications (versus illegal substances) and the misconception that they are "safe" may be contributing factors to their misuse. Hence, a major target for intervention is the general public, including parents and youth, who must be better informed about the negative consequences of sharing with others medications prescribed for their own ailments. Equally important is the improved training of medical practitioners and their staff to better recognize patients at potential risk of developing nonmedical use, and to consider potential alternative treatments as well as closely monitor the medications they dispense to these patients. As of April 2017, prescription drug monitoring programs (PDMPs) exist in every state. A person on opioids for more than three months has a 15-fold (1,500%) greater chance of becoming addicted. The CDC's "Guideline for Prescribing Opioids for Chronic Pain" offers many non-pharmacological options as alternatives to prescribing opioids. Physical therapist interventions is an example that is offered in regards to an alternative to prescribing opioids.
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.